(i) Field of the Invention
This invention relates to separator plates for use in electrochemical apparatus, e.g. batteries, electrodeposition apparatus, electrorefining apparatus or electromachining apparatus. The invention also relates to improved such apparatus incorporating such separator plates.
(ii) Description of the Prior Art
Some typical patents directed to storage batteries include the following:
Canadian Patent 1,041,165, issued Oct. 24, 1978, to Yuasa Battery Company Ltd., provided a lead-acid-type storage battery with embossed microporous separators. Each separator comprised microporous material made of synthetic resin and a macroporous base material. The separator had embossed parts that were poreless or substantially poreless.
U.S. Pat. No. 3,505,113, patented Apr. 7, 1970, by V. Merten, et al, provided a rechargeable energy conversion system utilizing zinc anodes and oxygen-providing cathodes. An aqueous alkali metal hydroxide electrolyte was circulated through the interior of the electrochemical cells and then exteriorly thereof, where it was cooled. The circulating electrolyte removed the zinc oxide reaction products from the cells during discharge, and these reaction products were separated from the electrolyte stream and stored exteriorly of the cells until the system was recharged.
U.S. Pat. No. 3,597,278, patented Aug. 3, 1971, by J. W. Von Brimer, provided an electrolytic cell comprising a positive electrode and a negative electrode, an electrolyte in association with said electrodes, and means for creating a magnetic field within the cell for circulating the electrolyte when current is flowing between the electrodes. One disclosed such means included permanent magnets extending between the plates forming the cell electrodes, to establish lines of the flux extending generally parallel to the plates and serving to maintain the plates in a spaced apart relation. The plates were microporous plastic to permit the electrolyte to permeate them, with permanent pagnets encased within the plastic.
U.S. Pat. No. 3,772,085, patented Nov. 13, 1973, by H. K. Bjorkman provided a diaphragmless secondary cell comprising a cell frame having an inlet means and an outlet means, a metal electrode held to the frame, a porous, supporting, conductive halogen electrode joined to the frame and spaced from the metal electrode, thereby forming an intercell spacing. The cell frame outlet means was positioned between the metal electrode and the halogen electrode of the cell. Means were provided for passing an aqueous metal halide electrolyte containing halogen into the cell frame inlet means to contact the halogen electrode by passing the electrolyte through the porous halogen electrode, into the intercell spacing and out the cell frame outlet means. A second cell frame inlet means was positioned adjacent to the metal electrode and spaced between the metal electrode and the halogen electrode in the intercell spacing and inclined at an angle of 5.degree. to 30.degree. from the metal electrode. Means were provided for passing electrolyte through the second inlet means towards the halogen electrode so as to produce a total electrolyte flow at a low Reynolds number adjacent to the metal electrode and to create a boundary layer of electrolyte thereon. Such boundry layer limited contact of the halogen with the metal of the electrode.
U.S. Pat. No. 4,042,754, patented Aug. 16, 1977, by D. Borells provided a battery comprising an outer housing bounding an internal battery compartment, and a cooperating negative and positive pair of battery plates disposed in spaced-apart relation in the battery compartment so as to subdivide the battery into a central electrolyte mixing compartment and separate first and second electrolyte inlet compartments on opposite sides thereof. Each negative and positive battery plate was comprised of a porous construction material for permitting the continuous flow of electrolyte components from the inlet compartments into the mixing compartment in accordance with a selected specific gravity of the electrolyte mixture in the central compartment optimum for electrical conductivity. The maintaining of the electrolyte mixture at the selected optimum specific gravity promoted effective charging and discharging of said battery plates.
U.S. Pat. No. 4,072,802, patented Feb. 7, 1978, by K. Murata, et al, provided a lead-acid storage battery comprising a container, at least one set of battery plates, one plate of the set being a positive plate and another being a negative plate, and a microporous separator interposed between the positive and negative plates. The microporous separator was a microporous sheet of heat-meltable, synthetic-resin containing thin film and having submicron micropores. The microporous sheet had a plurality of independent limited embossed parts projecting outwardly from the separator toward the positive plate. The projecting embossed parts were connected with projecting embossed channels which helped gas formed in the cell to escape upward out of the cell. The height of the projecting embossed channels were lower than the height of the projecting embossed parts, and the pores of the embossed parts were at least partially closed.
U.S. Pat. No. 4,346,150, patented Aug. 24, 1982, by Exxon Research Engineering Co., provided a cell construction including a stack of cells each comprised of an integral separator and spacer disposed between adjacent electrodes. Each electrode comprised a plastic sheet having a coextruded, electrically-conductive mid-portion and electrically non-conductive side portions.
U.S. Pat. No. 4,396,689, patented Aug. 2, 1983, by Exxon Research and Engineering Co. provided a cell construction including a stack of cells each comprised of an integral separator and spacer disposed between adjacent electrodes. Each electrode comprised a composite plastic sheet having a coextruded, electrically-conductive mid-portion and electrically non-conductive top and bottom side portions. The separator-spacer and the sheet electrodes were assembled by male and female connections which were hollow and which formed fluid conduits for the cells.
Some typical patents directed to electrolysis apparatus include the following:
Canadian Patent 1,056,904, patented June 19, 1979, by Yardney Electric Corporation, provided a separator for alkaline electrochemical cells having zinc negative electrodes. The separator comprised rare earth inorganic hydroxides in finely-divided solid particulate form dispersed uniformly within a shape-retaining, non-reactive matrix.
U.S. Pat. No. 3,522,162, patented July 28, 1970, by R. C. Davies, proposed a method and apparatus to cause migration of ions or electrically-charged particles in a solution by passing a body of solution through, and cutting across, a magnetic field. The magnetic field was generally radial and containers were spun through that field. The source of electrical energy used for obtaining an electrolytic reaction and for using migration of ions to the region at which electrolytic reaction took place was the movement of an electrolyte with respect to a magnetic field.
U.S. Pat. No. 4,093,533, patented June 3, 1978, by The Dow Chemical Company provided asbestos diaphragms for use in electrolytic chlor-alkali cells. The diaphragms were prepared by using polymeric fluorocarbons as binders for mixtures of chrysolite asbestos and crocidolite asbestos.
U.S. Pat. No. 4,165,271, patented Aug. 21, 1979, by Olin Corporation, provided a diaphragm for use in the electrolysis of alkali metal chloride brines in electrolytic diaphragm cells. The diaphragm was comprised of a support fabric impregnated with a non-fibrilic active component containing silica. The support fabric had a non-continuous coating of an electro-conductive metal on one side of the fabric.
U.S. Pat. No. 4,346,150, patented Aug. 24, 1982, by R. J. Bellows, et al, provided an electrochemical construction comprising a stack of cells each comprised of an integral separator and spacer disposed between adjacent electrodes, each comprised of a plastic sheet having a microporous center and a non-porous border and having a coextruded, electrically-conductive mid-portion and electrically non-conductive side portion.
U.S. Pat. No. 4,585,539, patented Apr. 29, 1986, by G. I. Edsen, provided an electrolytic reactor for the treatment of chemical species dissolved in electrically conductive solutions. That reactor included a sealed container and a microporous, electrically-insulating septum subdividing the container into first and second solution chambers. First electrode means were provided in the first solution chamber and second electrode means were provided in the second solution chamber. Static surface extension means, composed of discrete, particulate bodies, packed at least one of the solution chambers, in electrically conductive contact with the electrode in the chamber. First conduit means, including at least one inlet port and one discharge port were provided for the introduction of a first electrolyte into the first chamber and the withdrawal of electrolyte therefrom and second conduit means, including at least one inlet port and one discharge port were also provided for the introduction of a second electrolyte into, and the withdrawal thereof from the second chamber. Current supply means imposed a direct electrical potential across the first and second electrode means. Current reversing means were provided for reversing the potential applied across the first and second electrode means.
U.S. Pat. No. 4,675,259, patented June 23, 1987, by N. Shuster, et al, provided an electrochemical cell including a consumable anode defining a face and a cathode spaced from the anode face and defining a cathode face opposing the anode face, the cathode face and the anode face defining an electrolyte flow channel therebetween, the flow channel having an inlet and an outlet. Each of the anode face and the cathode was adapted to be in direct contact with an aqueous alkaline electrolyte during operation of said cell. A plurality of baffles was disposed in the electrolyte flow channel in contact with the anode and with the cathode face and defined an electrolyte flow path having a directional vector component perpendicular to a sufficient component of the flow vector of the electrolyte to increase the speed at which the electrolyte passed through the flow channel and across the anode face at any selected volumetric flow rate, as compared to an otherwise identical cell without such baffles.
Typical patents relating to electro-refining or electro-machining include the following:
Canadian Patent 935,780, patented Oct. 23, 1973, by The Mead Corporation, provided a method and apparatus to produce uniform apertures for use in a non-contact pinging system. An orifice plate was provided with pre-formed apertures or holes, the diameter of the holes being at least the size of the predetermined diameter desired. Liquid was supplied to the orifice plate under pressure. The liquid supplied was an electrolytic solution, and was flowed through each aperture or hole in the orifice plate. Suitable stimulation was provided at the orifice plate to cause uniform drop formation. After passing through the aperture, the liquid impinged on a contact bar. A potential difference was established between the bar and the orifice plate, with the electrolytic liquid completing the circuit so long as the unbroken filament reached the contact bar. As a result, metal from the electrolyte liquid was caused to deposit or plate on the wall of the apertures. An unbroken filament of liquid issued from the apertures, but had the tendency of subsequently breaking into drops. As the deposition built up on the inside of the aperture and decreased the diameter of the aperture, the filament length shortened, eventually NOT reaching and impinging on the contact bar. As a result, the electric circuit was opened, and deposition inside the apertures ceased.
Canadian Patent 1,089,408, patented Nov. 11, 1980, by Ultra Centrifuge Nederland N.V., provided an apparatus for removing material from electrically-conducting substances by electrochemical attack. The apparatus included a flow-guiding, non-conducting template which was equipped with one or more liquid inlets, liquid outlets, and efflux channels inside the template. The apparatus included a source of direct current, the negative pole of which was connected by way of a pulse generator which supplied current pulses of 5 to 20 milliseconds and a resistor which was connected in parallel to a current integrator, and to electrodes, which were provided in the efflux channels in the flow guiding template at a distance from a work piece to be machined. The positive pole of the source of direct current was connected to the work piece.
Typical patent directed to fuel cell constructions include the following:
U.S. Pat. No. 3,881,956, patented May 6, 1975, by T. S. Williams, provided a parallel electrolyte feed, parallel electrolyte drain stacked array of fuel cells with a common electrolyte supply and common electrolyte drain electrically connected in series. Such structure also included a plate at an end of the stack with transverse conduits therein, and a first imperforate electrolyte feed conduit running along a marginal edge of the stacked cells essentially parallel to the direction of stacking and interconnecting the common electrolyte supply with an end of a first one of said transverse passages to define therewith an elongated electrolyte feed passage bypassing the cells in the stack. A branched electrolyte feed channel ran along a marginal edge of the stacked cells and had a feed end connected to an end of the first transverse conduit to define a branched passage receiving electrolyte from the first transverse conduit and supplying the electrolyte to the cells in parallel. A second imperforate electrolyte drain conduit ran along a marginal edge of the stacked cells essentially parallel to the direction of stacking and interconnected the common electrolyte drain with a second one of the transverse passages to define therewith an elongated electrolyte drain passage bypassing the cells in the stack. A branched electrolyte drain channel ran along a marginal edge of the stacked cells and had a drain end connected to an end of the second transverse conduit and drained electrolyte from the cells in parallel.
U.S. Pat. No. 4,037,022 patented July 19, 1977 by J. Cheros, provided a fuel cell block comprising sealed compartments for fluid reactants and electrolyte, these compartments being delimited by plates, for example, the electrode of the fuel cell. At least some of the plates delimiting the compartments were subjected to magnetic attractive forces balancing the action of the pressing forces exerted on these plates by the fluid contained in the compartments.
A problem which has been found to exist in attempting to maximize the electric current produced by storage batteries (as described hereinabove) is the internal resistance of the cell. It would, therefore, be desirable to provide a structure for use in such a cell which would result in a reduction of the internal resistance and, hence, would provide more electric current.
However, a problem in electrolysis cells (as described above) not addressed by the prior art, is the adequate stirring of the electrolyte. The prior art technique of stirring inevitably resulted in the motion of the electrolyte being transmitted in diminished velocity to the electrode surface. It would, therefore, be desirable to provide a structure for use in such cells which would result in an optimum stirring of the electrolyte.
A problem with the prior art methods and apparatus for electro-refining or electro-forming, (as described above), is that these methods and apparatus are not adapted for the production of "square" holes.